Color photographic development process

ABSTRACT

THE SENSITIVITY OF COLOR PHOTOGRAPHIC MATERIAL IS INCREASED AND ITS IMAGE GRAIN SIZE REDUCED BY TREATING THE MATERIAL AFTER COLOR DEVELOPMENT AND BEFORE BLEACHING, WITH AN AQUEOUS ALKALINE BATH CONTAINING PER LITER 0.01 TO 1.0 GRAM OF A BLACK-WHITE DEVELOPER OF THE P-AMINOPHENOL OR 1-PHENYLPYRAZOLIODINE SERIES. THE BATH MAY CONTAIN ANTIOXIDANTS, ALKALI METAL SULFITES, SEQUESTERING AGENTS AND STABILIZERS.

United States Patent 3,552,966 COLOR PHOTOGRAPHIC DEVELOPMENT PROCESS Gerhard Kuhn, Leverkusen, Albin Graf, Munich, Franz Moll, Colognestammheim, and Rigobert Otto, Leverkusen, Germany, assignors to Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany N0 Drawing. Filed May 24, 1967, Ser. No. 640,825 Claims priority, application Germany, July 2, 1966,

Int. Cl. G03c7/30, 7/40 US. Cl. 96-54 3 Claims ABSTRACT OF THE DISCLOSURE The sensitivity of color photographic material is increased and its image grain size reduced by treating the material after color development and before bleaching, with an aqueous alkaline bath containing per liter 0.01 to 1.0 gram of a black-white developer of the p-aminophenol or l-phenylpyrazolidone series. The bath may contain antioxidants, alkali metal sulfites, sequestering agents and stabilizers.

The invention relates to an improved process for developing color photographic materials by using after color development a bath containing black-white developers.

Many different ways of modifying the color development of color-photographic materials are known for achieving improved color densities, sensitivity, etc. Thus, for example, it has been stated that when developers that are used for black-white films, such as aminophenols, are added to a conventional color-forming developer, a higher yield of dye is observed in the developing of color photographic layers, especially in the blue-green layer. However, this is generally accompanied by undesirably coarsening of the grain and in addition, the improvement in the cyan density is in many cases associated with reduction of the magenta density.

It is also known to enhance the sensitivity of the colorphotographic material by additional baths which are to be applied after color development. These baths generally contain inorganic salts, for example, potassium bromide. This modified procedure, also however, leads to a coarser dye grain, which is a serious disadvantage from the point of view of the quality of the final dye image.

It is the object of the present invention to improve the processing of color photographic materials, so as to obtain an enhanced sensitivity with as small as possible grain size.

We now have found that the sensitivity of color photographic materials, in particular color negative films, is substantially enhanced if the exposed and developed material is treated with an after-treatment bath which contains black-white developers, especially of the aminophenol type or of the pyrazolidone type. At the same time, a dye image of considerably finer grain is obtained.

Suitable developers of the p-aminophenol series are the following:

p-aminophenol p-N-methylaminophenol p-N-2-hydroxyethylaminophenol 1-hydroxy-3,4-diaminobenzol l-hydroxy-Z,5-dimethyl-4-aminobenzol 1-hydroxy-2-methyl-4-aminobenzol 1-hydroxy-2-hydroxymethyl 4-aminobenzol 1-hydroxy-3-methyl-4-aminobenzol.

Suitable developers of the l-phenylpyrazolidone series are described in US. Pat. No. 2,289,367.

The after-treatment bath to be used according to the invention contains, apart from the black-white developer,

"ice

the usual further additives, the concentrations of which are not critical and depend on the kind of the color-photographic material processed. We have found that generally after-treatment baths of the following composition are quite adequate to accomplish the desired results:

G. Blackand-white developer 0.01-1 Preferably 0.05-0.5

Antioxidants such as hydroxylamine l4 Alkali metal sulfites 2-10 Sequestering agents such as sodium hexameta phosphate 1-5 Stabilizers such as potassium bromide 0.2-0.5 Alkalizing agents such as sodium or potassium carbonate, alkali metal phosphates or borates, alkali metal hydroxides or the like 1 0-20 Water up to 1 l.

The after-treatment bath according to the invention preferably has a pH of between 8 and 12 and in particular between 9- and 10.

The color developers to be used in the process according to the invention have the usual composition. As color developers it is preferred to use developers of the p-phenylene diamine type. The color developer may also contain development accelerators such as quaternary ammonium salts, polyethyleneoxides or derivatives such as spirocyclic phosphoric esters of polyethyleneglycol. Black-white developer compounds may be added to the color developer.

EXAMPLE Samples of a multi-layered color photographic material of the usual composition with a red-sensitive silver halide gelatin emulsion layer arranged on the support, which layer contains color couplers that react with the oxidation product of the color-forming developer to form the cyan image, a green-sensitive silver halide gelatin emulsion layer arranged on the red-sensitive layer, which green-sensitive layer contains color couplers for the magenta image, a yellow filter layer and uppermost a silver halide gelatin emulsion layer containing color couplers for producing the yellow image, are exposed behind step wedges in a conventional sensitometer and processed as follows:

Processing Method A Color developer: G. Sodium hexametaphosphate 2 p-N,N-diethylphenylenediamine 2 Hydroxylamine sulfate 2 Sodium sulfite sicc 2 KBr 1.5 Potassium carbonate 50 Make up to 1000 ml., the pH being 10.8.

Development time 10 minutes at 22 C.

Short stop bath-treatment time 4 minutes:

Sodium acetate15 g.

Make up with water to-1000 ml.

Then add glacial acetic acid to pH 4.0.

Rinsing in water 8 minutes.

Bleaching bath-treatment time 4 minutes: G. Sodium hexametaphosphate 5 Potassium ferricyanide 60 KBr 15 Disodium phosphate 1 Water up to 1000 ml. Rinsing 4 minutes. Fixing-bathtreatment time 6 minutes:

Sodium thiosulfate cryst.200 g. Water up to1000 ml. Rinsing again for 4 minutes. Final bath in wetting agenttreatment time 1 minute.

3 4 A suitable wetting agent bath is, for example, an ap- Processing is continued as under A, including the short proximately 0.1% aqueous solution of the sodium salt of stop bath. paraffin sulfonic acid. Processing Method D Processmg Method B The same as method A but Without the short stop bath. Color developer as under Adevelopment time 10 min- 5 The results of the sensitometric test are shown in the utes. following table:

TABLE A B o D Yellow Magenta Cyan Yellow Magenta Cyan Yellow Magenta Cyan Yellow Magenta Cyan 4 1 2 2 2 +1 +1 +1.5 +3 +3 +4 +1.5 +1.5 +2 11 52??? 0. 2 3 0. l 8 0. 1 6 0. 28 0.20 0.18 0. 32 0.22 0.22 0.32 0.29 0. 26 Gamma- 0. 69 0. 02 0.66 0.67 0. 60 0. 64 0.62 0.57 0. 00 0. 02 0.60 0. 00 Grain Standard Same to coarser Finer Coarser 1 In 0.1 log Lt. units (DIN). 2 Standard. After development bath-treatment time 4minutes: G. The above figures represent average values obtained Sodium sulfate 30 f om several measurements. The superiority of processing KBr 0.25 20 m th d C according to the invention is readily apparent.

What is claimed is:

1. In the process for producing color-photographic The pl'ocedllre is then cohtlhued as In Method images in complementary colors from a negative film by cluding the short stop bath. developing exposed color-photographic material with a color-forming, developer of the p-phenylene diamine se- Make up to 1000 ml., and adjust pH to 10.0.

Processmg Method c 20 ries, then bleaching and fixing the developed material, the

Color developer as under Adevelopment time 10 minimprovement according to Which the Color developed utes. color-photographic negative material has its sensitivity increased and its image grain size reduced by treating it After treatment at according t0 the lhveht10htreat' 30 after the color developing bath and before bleaching with ment time4minutes: an aqueous alkaline bath containing 0.01-1 g. per liter Borax-15 g. of a black-white developer of the p-aminophenol or 1- KBr0.5 g. phenylpyrazolidone series.

Sodium sulfite sicc.2 g. 2. The combination of claim 1, wherein the aqueous Hydroxylamine2 g. 35 alkaline bath has a pH of between 8 and 12. 1-phenylpyrazolidone-(3)150 mg. 3. The combination of claim 1 in which the aqueous Make up to 1000 ml. and adjust pH to 9.25. alkaline bath has a pH between 9 and 10.

References Cited FOREIGN PATENTS 811,185 4/1959 Great Britain 96-55 NORMAN G. TORCHIN, Primary Examiner A. T. SURO PICO, Assistant Examiner US. Cl. X.R. 9655 

